L. Hansen et al., Studies of variability in the PTEN gene among Danish caucasian patients with Type II diabetes mellitus, DIABETOLOG, 44(2), 2001, pp. 237-240
Aim/hypothesis. Phosphatase and tensin homologue deleted from chromosome te
n (PTEN) has recently been characterized as a novel member in the expanding
network of proteins regulating the intracellular effects of insulin. By de
phosphorylation of phosphatidyl-inositol-(3, 4, 5)-trisphosphate (PIP3) the
PTEN protein regulates the insulin-dependent phosphoinositide 3-kinase (PI
3K) signalling cassette and accordingly might function as a regulator of in
sulin sensitivity in skeletal muscle and adipose tissue. In this study we t
ested PTEN as a candidate gene for insulin resistance and late-onset Type I
I (non-insulin-dependent) diabetes mellitus in a Danish Caucasian populatio
n.
Methods. The nine exons of the PTEN, including intronic flanking regions we
re analysed by PCR-SSCP and heteroduplex analysis in 62 patients with insul
in-resistant Type II diabetes.
Results. No mutations predicted to influence the expression or biological f
unction of the PTEN protein but four intronic polymorphisms were identified
: IVS1-96 A-->G (allelic frequency 0.22, 95% CI: 0.12-0.32), IVS3+99 C-->T
(0.01, CI: 0-0.03), IVS7-3 TT-->T (0.10, CI: 0.03-0.18) and IVS8 + 32 G-->T
(0.35, CI: 0.23-0.47). The IVS8 + 32 G-->T polymorphism was used as a bi-a
llelic marker for the PTEN locus and examined in 379 patients with Type II
diabetes and in 224 control subjects with normal glucose tolerance. The IVS
8+32 G-->T polymorphism in the PTEN was not associated with Type II diabete
s and it did not have any effect on body-mass index, blood pressure, HOMA i
nsulin resistance index, or concentrations of plasma glucose, serum insulin
or serum C peptide obtained during an oral glucose tolerance test (OGTT).
Conlusion/interpretation. Variability in the PTEN is not a common cause of
Type II diabetes in the Danish Caucasian population.